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Process for preparing chloroacetaldehyde acetals

a chloroacetaldehyde and acetaldehyde technology, applied in the field of chloroacetaldehyde acetaldehyde acetal preparation, can solve the problems of poor yield, low yield, and high cost of preparation

Active Publication Date: 2018-02-20
WACKER CHEM GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patent describes a simple process to get high-purity chloroacetaldehyde acetals using an alcohol and an acid catalyst. By using a halogenated solvent, the process can even work with low-boiling alcohols. It is especially useful for acid-sensitive chloroacetaldehyde acetals as the acid can be neutralized with amines before distillation. The process is efficient and produces little waste. The solvent or mixture of solvent and alcohol can be reused without further purification. Overall, this patent provides a simple and efficient way to get high-purity chloroacetaldehyde acetals.

Problems solved by technology

This process for preparing the required trimer of chloroacetaldehyde is very complicated, requires large amounts of solvent and concentrated sulfuric acid and gives a poor yield (about 50%), so that this process is not industrially relevant.
However, these water-binding agents not only make the preparation expensive but also form a considerable amount of waste which in the case of the chlorinated aldehydes is difficult to dispose of because of the content of chlorinated constituents.
In addition, 80% strength chloroacetaldehyde is difficult to prepare and also not readily handleable because of the decomposition potential.
However, there is no known industrially relevant process which is suitable for preparing chloroacetaldehyde acetals from aqueous chloroacetaldehyde solutions.
Only processes which start out from chloroacetaldehyde hemihydrate, which is difficult to prepare and owing to the possibility of decomposition is dangerous to handle, are known.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

on of 2-chloromethyl-1,3-dioxepane

[0029]1744.4 g of 45% strength aqueous chloroacetaldehyde solution (10 mol of chloroacetaldehyde), 919.0 g (10.2 mol) of 1,4-butanediol, 1 l of trichloromethane and 2 g of p-toluenesulfonic acid were placed in a 4 l four-neck flask provided with water separator, reflux condenser, precision glass stirrer and internal thermometer. The two-phase mixture was heated under reflux on the water separator while stirring until no more water separates out (about 10 hours). The reaction mixture here became a single phase. The reaction mixture was then distilled under reduced pressure (15 mbar, 80° C.)

[0030]Yield: 1459.3 g (96.9%), purity >99% (GC)

example 2

on of Chloroacetaldehyde Diethyl Acetal

[0033]2442 g of 45% strength aqueous chloroacetaldehyde solution (14 mol of chloroacetaldehyde), 1612 g (35 mol) of ethanol, 1500 ml of trichloromethane and 2.8 g of p-toluenesulfonic acid were placed in a 6 l four-neck flask provided with water separator, reflux condenser, packed column, precision glass stirrer and internal thermometer and metering unit. The two-phase mixture was heated under reflux on the water separator while stirring until no more water separates out (7 hours). The reaction mixture here becomes a single phase. A further 322.5 g (7 mol) of ethanol were then introduced under reflux and with separation of water. Another 253.7 g (4.35 mol) of ethanol and also 500 g of trichloromethane were subsequently added and the mixture was heated under reflux on the water separator until no more water separated out. 31.2 g of tributylamine are subsequently added to effect neutralization and the reaction mixture is fractionally distilled un...

example 3

on of 2-chloromethyl-1,3-dioxolane

[0035]174.44 g of 45% strength aqueous chloroacetaldehyde solution (1 mol of chloroacetaldehyde), 68.28 g (1.1 mol) of ethylene glycol, 200 ml of trichloromethane and 0.2 g of p-toluenesulfonic acid were placed in a 1 l four-neck flask provided with water separator, reflux condenser, precision glass stirrer and internal thermometer and metering unit. The two-phase mixture was heated under reflux on the water separator while stirring until no more water separates out (total of about 7 hours). The reaction mixture here becomes a single phase. 2.2 g of tributylamine are then added to neutralize the p-toluenesulfonic acid and the reaction mixture is distilled under reduced pressure (75 mbar, 85° C.)

[0036]Yield 111.6 g (91%), purity >99% (GC)

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Abstract

The invention relates to a process for preparing chloroacetaldehyde acetals of monohydric, dihydric or higher-functionality aliphatic alcohols, in which the chloroacetaldehyde acetal is obtained from an aqueous chloroacetaldehyde solution in the presence of the alcohol to be acetalized and an acid catalyst by azeotropic removal of water with the aid of a solvent, wherein the solvent is a halogenated solvent.

Description

BACKGROUND OF THE INVENTION[0001]The invention relates to a process for preparing acyclic and cyclic chloroacetaldehyde acetals from aqueous chloroacetaldehyde solutions by azeotropic removal of water with the aid of a suitable solvent.[0002]It is known that chloroacetaldehyde acetals can be prepared by chlorination of vinyl compounds (vinyl acetate, vinyl chloride, vinyl ethers) in alcoholic media. A discussion of this prior art may be found in U.S. Pat. No. 4,440,959.[0003]EP0456157B1 describes the preparation of chloroacetaldehyde acetals from the trimer of chloroacetaldehyde in good quality and yield. The trimer of chloroacetaldehyde used for the preparation is described in EP0368613B1. This process for preparing the required trimer of chloroacetaldehyde is very complicated, requires large amounts of solvent and concentrated sulfuric acid and gives a poor yield (about 50%), so that this process is not industrially relevant.[0004]It is also known that acetals can be prepared by m...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C07D321/06C07C41/09C07D319/06C07C41/56
CPCC07D321/06C07C41/09C07C41/56C07D319/06C07C43/313C07D317/16
Inventor KRUEGER, BENNODOERING, WOLFGANGFLEISCHMANN, GERALDPETERSEN, HERMANN
Owner WACKER CHEM GMBH